1. Field of the Invention
The present invention relates to a cannulated screwdriver for arthroscopic surgery and, more specifically, to a pin-lock cannulated screwdriver which can be fixed in relation to a guide pin during endosteal fixation of a ligament by screw insertion.
2. Description of the Related Art
Endosteal fixation of a substitute ligament or graft is well known in the art. See, e.g., Kurosaka, et al., "A Biochemical Comparison of Different Surgical Techniques of Graft Fixation in Anterior Cruciate Ligament Reconstruction," Am. Jour. Sports Med., Vol. 15, No. 3, pp. 225-229 (1987). When a ligament or tendon becomes detached from a bone, surgery is usually required to resecure the ligament or tendon. Often, a substitute ligament or graft is attached to the bone to facilitate regrowth and permanent attachment. Various methods of graft attachment are known, such as staples and sutures over buttons. However, such methods often do not provide a sufficiently strong attachment to withstand the normal tensile loads to which they are subjected.
A stronger graft attachment is obtained by using an interference screw to wedge a graft bone block to the wall of a graft tunnel formed through the bone. FIG. 1 illustrates this method, in which the graft 2, with bone blocks 4,6 at each end, is pulled through a graft tunnel 8 in the tibia 10 by applying a tensile force on sutures 12 attached to leading bone block 6. The leading bone block 6 is brought forward into the femur 14 until it is fully nested in a graft tunnel in the femur. Then, with tension applied to the graft 2 via sutures 12, a screwdriver is used to insert interference screws 16 between the bone blocks 4,6 and the graft tunnel, first in the femur and then in the tibia.
A guide pin is often used in conjunction with a cannulated interference screw (and a cannulated screwdriver) to properly locate the screw against the bone block. However, inserting the guide pin is cumbersome, because the pin tends to bend and is difficult to grip. Moreover, even when the guide pin is properly located, the surgeon has to eye the correct depth of the insertion of the pin. Also, handling the guide pin and screwdriver as separate pieces is inconvenient during surgery.